how to use a texture on each side of the same face
Same as above but using Blender Render - it has to use nodes, there isn't a way without it. By using the Geometry node, I plug the Front/Back input to the Factor of the color mix node that is sent to the material color node. At this stage, you can then plug your image textures into the two colors of the color mix node, and indicate the UV Map name there in the Geometry node.